Machine for slitting tires



Feb. 1960 F. ,c. MESERVE ET Ag. 2,924,267

MACHINE FOR SLITTING TIRES 3 Sheets-Sheet 1 Filed March 29, 1954 INVENTORS 'zwww @Z Feb, 9, 1960 F. c. MESERVE ETAL 6 MACHINE FOR SLITTING TIRES Filed March 29, 1954 s Sheets-Sheet 2 lllll lllllliillllit IN V EN TORS:

l 7 5 6 M XZI Q Feb. 9, 1960 F. c. MESERVE ETAL 2,924,267

MACHINE FOR SLITTING TIRES Filed March 29, 1954 3 Sheets-Sheet 5 I 01 P64 63- ll 7 1 J6 I 6F l I FF 5 F IN V EN TORS MACHINE FOR SLITTING TIRES Forrest Clayton Meserve, Andover, and Minot F. Smith,

Welle'sley, Mass., assignors to Micro Machinery Products, Inc., Winchester, Mass, a corporation of Massachusetts Application March 29, 1954, Serial No. 419,144 3 Claims. c1.'1s7--13 This invention comprises a novel machine employing a continuously running knife for cutting or slicing tires, operations being carried out either while the tire remains in place on the wheel of the vehicle or while independently supported. I

It has been found beneficial in the treads of pneumatic tires to provide closely spaced transverse slits which function to provide the' tire with certain desirable anti-skid properties in use and which augment the braking effect and so increase in general the safety of driving. The depth to which the surface slits may be extended into the tread of a new tire by existing means is limited to about A inch but it has been found desirable to form deeper slits in many cases and also to supply additional transverse slits to worn tire treads in order to restore them to their original effective condition after they have been worn down in use.

An object of the present invention is to provide a tire cutting machine so constructed and arranged that tire treads may be deeply and uniformly slitted without removing the tire or the wheel from the vehicle. In this connection, accordingly, an important feature of our invention comprises spaced rolls or other rotatable means for supporting a vehicle wheel off the ground in position where it may be rotated for cutting, in combination with a chain type of slitting mechanism arranged to operate on the tire while so supported.

Another important feature of our invention comprises a continuously running blade-carrying chain. Such a chain may advantageously be assembled and operated with means for intermittently rotating the tire, or by guiding the blade-carrying chain in a path inclined to-the axis of rotation of the tire, the tire may be rotated continously during the slitting operation. In the latter case the slits will be formed at a slight transverse angle, that is to say, they will not be parallel to the axis of rotation of the tire. It has been found, however, that such variation in the angle .of the slits is in no way undesirable or at all detrimental to the desired results and that it substantially expedites the whole operation. In one aspect, therefore, the invention comprises a process of slitting pneumatic tires which is characterized by the steps of rotating the tire and passing a chain-carried slitting knife through the tread thereof in a path at an inclination to its axis of rotation while the tire is in motion.

Going more into detail, our invention includes as an important feature an endless chain mounted to travel over sprocket wheels located on opposite sides of the plane of rotation of the tire and guided in a path transversely beneath the tire. This carrier chain is equipped with spaced series of slitting blades that increase progres sively in effective height so that each cut is madein a shearing manner and the formation of closely spaced clean-cut slits is thus facilitated.

These and other features of the invention will be best understood and appreciated from the following descrip- 'ice poses of illustration andshown in the accompanying, v drawings in which:

Fig. 1 is a vlew tire in operative position for slitting; v v

Fig. 2 is a fragmentary view in perspectivqpf the blade-carrying chain,

Fig. 3 is a view in elevation at right angles-to'thatt of Fig. 1,

Fig. 4 is a view in elevation with parts removed to disclose the tire feeding roll 17,

Fig. 5 is a plan view of a machine embodying the invention in a modified form,

1 Fig. 6 is a correspondlng'vievv in end elevation, and l;

Fig. 7 is a fragmentary sectional view on the line 7--7 of Fig. 5 and on an enlarged scale. I

The machine shown in Figs. 1-4 comprises a base 10 to which are bolted a pair of upstanding bearing brackets 11 for a transverse shaft 12 and a spaced pair of npstanding bearing brackets 13 for a transverse shaft 14. The shaft 14 carries at its inner end as shown in Fig. 4v a sprocket wheel 15 over which runs an endlesssprocket, I chain 16 geared to a similar sprocket wheel (not shown); on the inner end of the shaft 12. The shaft 14carries'- a fluted tire supporting roll 17 and the shaft 12 carries a corresponding fluted roll 18. These two rolls C Olc-' lectively provide a cradle for rotatably supporting a tire and they are geared together through the medium'of the 1 sprocket chain 16 so that they can rotate vonly atthe same speed.

The shaft 14 has a ratchet wheel .19: fast toit adjacent to the inner bearing bracket 13 and with the ratchet] wheel operates a pawl 20 pivotally mounted upon: an; oscillatory arm 21. The arm 21 is connected through a. rod 22 to a depending cam arm 23 pivotally mounted at its upper end by a pin 27 onv a stationary bracket 2 4 This bracketis securedto a bearing bracket 25pm jecting upwardly from 'thebase" and in it is journaled a third transverse shaft 25. The shaft 25 has fast upon its rear end a cam 29 having a single throw in its pe-.- riphery and cooperating with a cam roll 28 carried by the cam arm 23. In each revolution of the shaftu25,

therefore, the cam arm 23 is given one complet e osc illation and the ratchetwheel 19 advanced a corresponding distance, for example, two teeth at atime, this being...

sutficient to impart a rotary movement of about 0.017 to the tire.

At its front end the shaft 25 carries a bev meshing with a corresponding bevel gear 31 on the upper, end of a shaft 32 journaled in a bearing bracket'441 which projects upwardly and at an outward inclination" from the base 10. The shaft 32 also carries a sprocket" wheel 33 and the bracket 44 carries a triangular frame 34 which is disposed in substantially radial relation'to, the tire being slit. The frame 34 carries at its u per portion sprocket wheels 35, 36 and 37 over which, and I the sprocket wheel 33, a sprocket chain 38 runs in a triangular path. The chain as shown in Fig. 2 carries. on each link a block 39 to the opposite edges of which are secured slashing blades 40. As shown in Fig. the

chain is driven in a clock-wise direction. N y The slashing blades 40 are arranged in severalseries spaced from each other to provide abrief-tire-feeding interval between the cutting of successive slits. The, blades of each series progressively increase in efiective' height so that each slit is formed in a slashinggor draw In the latter case two slits will be formed at once and the length of the tire feeding steps correspondingly eased. e ,u 1 1 of the machine in elevation showing a l gear 30 forms =As-shown-in Fig; 3 "the upper sprocket wheels 35, 36

- and 37 are so located as to guide the chain 38 in a curved path conforming tothe transverse contour of tires! '42 such as-'- would be found on i the duplex wheels of a truck, but it will be understoodLthat-thepath o'f the chainmay be adjusted *for any desired contour by adjusting the position of the guiding s'procket wheels." The several groups or series of slitting blades 40 are.

disposed in spacedrelation upon the chain '38; forexariiple; as h'erei'n shownfifteen blank blocks occur between each series of three or six blades, This spacing of; the slitting blades is such that the step ,of. rotatiriggthe tires may beeffected in the intcrval between theeinerge'nce of one-series ofblades or pair er series fromthe 'tread of the tire and the entrance bfthenext following series or painof series, of blades. The frame 3-! is provided with an open 'channel' in'which the blocks 39,.of the chainare confined and guided in their travelbeneathnbe tiresi 'The machine is preferably provided with a rarnp 45 5"in pitch diameter and provided with right-hand worm threads, 13 to the inch,modified in contour so that they have an effective driving bite on the the being slitted at both sides of the circumferential recess of the drum.

A curved bar 61 is supported at itsopposite ends by the brackets 63 and 65 and extendstransversely through the recess betweefi the drum sections-;5;1;and;5 2; It is pro-. vided in its upper concave face witha guide track for 1 thechain 55 andpthisitrack extends at an opposite angle,

toithe direction of the'wcrm threadspf the drum sections. It supports the chain for movement in an oblique concave path corresponding transversely toythe contour of the tire 42,'fwith..the slittingtknives projecting above the threads by the depth, ofpthe desired slitting.

The shaft 62 is connected through a universal joint 66 t to a shaft 67 journaled in the upper end of the bearing bracket 68 and, this shaft carries at its outer end a sprocket Wheel 69,,over-which runs a sprocket .chain 70 connecting by which'thewhed 'or'fwheels 43 having the, tires 41 and 42*t c be=slit'mayfbeeasily rolled up into supported positionupon therolls '17 and 18.. If-it is desired' to slit the tireson pnmounted'jwheels, the wheels may be Jmere- 1y -lifted into positi'on and supported forrota tion'by any convenient means.

' "f-Theshaft constitutes aicoml mon actuator for the blade-carrying chain andthe tire .rotating'ratchet mech- 'a nis rn and maybe driven at a uniform speed from any convenient source of 'power. "When so operated it will be understobdthatwhile the pawl 21 is at rest or making its idle strokeyone series of slitting blades '40 on" the chainf 38"willbedrawn through the treads 'of the tires. Then-as theseblades emerge the pawl '20 will make its operativeistrok e and the tire will be advanced into position 'forthe next pair of slitting blades; Two slits may be made {at each operation withfdouhle the'spacing of displacement bythe guidechannel in thefra'me'34 so that. I

it canuot'bedrawn'out' of jlineb'y the friction of the tire treadas,;the tire is rotated. The guid'e'ch'annel has no ccnstrainingefiecton thech'ain' in preventing it from conforming to thetransverse contourof the tread.

52 spanning the recess betweenthem and in thisposition the tire-maybe either mounted onthertruck or vehicle s be the distance (between adjacent slits 71 in the tire, :and t In a modifiedconstruction of our invention, as, shown in'l-"igs.' 5'to '7, .WecmpIoyaLthreadjed drum or' cylinder feeding function. Asshown in these figures, J

a horizontal sh'aftj50 mountedin bearing brackets 53 and SScarrie s threaded drum sections 51 and 52, These sectionsr'na'y be part of a single drum and separated by a circumferential recess, or they maybe formedseparately and keyed to the shaft. Atits front end, the shaft carries a sprocket wheel 54. and 'atits rear end, it may be ex tended for any convenient driving connections(notl shown) .1]The.dr uni ishereinshow'n as having a helical right-ihand thread and driven in, clockwise direction as seenfiri Fig. 6, andso rotating theftir e upwardly .in the side toward the "observer.- n a secured. by employing a drurnhwith a left-hand thread and rotating 'it counter-clockwise.

Thet'irefslitting means herein shown comprises achain 55jhavingroll'sw56 that mesh jvvith sprocket wheels 59. and 6flf-Toleach link of the chain is secured a =fiat The. same result would be.

it to .the sprocket wheel Men the driving shaft 50} In operation the tire 42-to be slittedis placed"in posi-' tion to rest symmetrically on the drum sections 5 1jand wheel) or provided with other supporting means. ,When the shaft 50 is :driven, the .worm,,threads'indent andlrotate' the tire continuouslyin wormand wheel fashion and at auniform rate in the direction of the arrow'gin Fig. 6.

At the same time, the" chain with its slitting blades 58isdrivenfrbm left-to right and the blades from the} slits-7i as indicatedinFig. 6, these'being inclined atan' acn'teangle of about-8f to the axis of the tire. The spacing of the blades on-the chain is such as to give eachseries' of'blades time to perform its ,slitting opera tion and this is followed by interval of no slitt ing while the blank blocks'57 pass beneath the tireand the tire itself is rotated to bring its tread into position for the next slit. It will be understood that the spacing o f'the blades 58 -and the speed of the chain is synchronized with the rotational movement of the tire effected by "the threaded sections 51 and 52; The greater theinterval,

between the 'consecutivejblade series, the greater will this maybe regulated to unit the requirementsof the work in hand. The speed of the chain is preferably such that the leading blade is carried forward in the tire a distance corresponding tothe pitch of thef threadfas the blajde passes from one edge of the thread'to the other.

Having thusdisclosed our invention and described in newand desire to secure by Letters Patent:

detail an illustrative'enibodiment thereof, we claim as t 1.-A;tir'e',cutting machine comprising means for sup porting and rotating a tire, in combination with a carrier chain guided in a path transverse to thetire, and several" series of slitting knives mounted permanently in longitudinal procession on thechain and projecting therefrom, each series being separated by an interval andtlieknives of each series progressively increasingin effectiveheight,

top'ped forked block 57 and upstanding slitting blades 58 a a are secured to'thes'e'blocks in spaced series'and graduated effective height as described in connection with Fig. '3, The 'sprjocket wheel 59 is mountedon a shaft 62 journaled in the upper end-of a bearing bracket 63 and disposed-at anifiuclination to the axis of the shaft 50 opposite to thepit'ch angle of the threads on the;dr unr sections 51 and 52. In practice, these sections may be the lower height portions of the knives' being set to enter the tire firstand theknives thus cuttingprogressivelydeeper as they' pass through the tread of the tire and so operating to make a slicing cut. 1

2. A'tire slitting machine comprising a continuously rotated drum having tire-indenting threads and anfintermediate circumferential recess interrupting the threads, means forsupporting a tire for rotation about an, axis at right angles to that of the drum and in position to be] indented by said threads on bothsides of the recess and H to be rotated .by. the threads, a carrier chain passing through-the recess in'apath inclined tothe axis of the drum, andjslitting -blades'. attached to the chain and projecting beyond the threads of the. drum, thereby slitting the tire in'an area between its pqintsof engagement-with said threads. H

.3.- ..A, rtire slitting .ntachine ,asfidese ihsd tin. cl im 12... further characterized in that a curved track extends transersely through the said recess of the drum and the chain is guided and supported by this track while slitting the tire.

References Cited in the file of this patent UNITED STATES PATENTS 1,730,585 Midgley Oct. 8, 1929 1,737,146 Castricum Nov. 26, 1929 1,771,722 Prentice July 29, 1930 10 1,894,347 Dacon et al. Jan. 17, 1933 2,015,635 Errig et a1. Sept. 24, 1935 6 Piquerez July 28, 1936 Fleming Jan. 11, 1938 Errig et a1. Feb. 27, 1940 I-Iufi Nov. 20, 1951 Jakku Dec. 28, 1954 James Sept. 13, 1955 Meserve et a1. Apr. 10, 1956 FOREIGN PATENTS Great Britain 1912 Austria Mar. 10, 1932 Germany May 31, 1922 

